Combining temperature-dependent life table data into Insect Life Cycle Model to forecast fall armyworm Spodoptera frugiperda (JE Smith) distribution in maize agro-ecological zones in Africa

PLoS One. 2024 May 6;19(5):e0299154. doi: 10.1371/journal.pone.0299154. eCollection 2024.

Abstract

The fall armyworm (FAW), Spodoptera frugiperda (JE Smith) (Lepidoptera: Noctuidae), an invasive agricultural pest, has significantly impacted crop yields across Africa. This study investigated the relationship between temperature and FAW life history traits, employing life cycle modeling at temperatures of 20, 25, 28, 30, and 32°C. The development time for eggs, larvae, and pupae varied from 0-3 days, 10-18 days, and 7-16 days, respectively. The optimal temperature range for immature stage survival and female fecundity was identified as 21-25°C, with the intrinsic rate of increase (rm) and gross reproductive rate (GRR) peaking at 25-28°C. Model validation confirmed the accuracy of these findings. The research further projected the Establishment Risk Index (ERI), Activity Index (AI), and Generation Index (GI) for FAW under current and future climates (2050 and 2070) using RCP 2.6 and RCP 8.5 scenarios. Results indicate that RCP 2.6 leads to a reduction in high-risk FAW areas, particularly in central Africa. Conversely, RCP 8.5 suggests an increase in areas conducive to FAW activity. These findings highlight the impact of climate policy on pest dynamics and the importance of incorporating climatic factors into pest management strategies. The study predicts a potential decrease in FAW prevalence in West Africa by 2070 under aggressive climate mitigation, providing a basis for future FAW management approaches.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Africa
  • Animals
  • Female
  • Larva / growth & development
  • Larva / physiology
  • Life Cycle Stages*
  • Life Tables
  • Spodoptera* / growth & development
  • Spodoptera* / physiology
  • Temperature*
  • Zea mays* / growth & development
  • Zea mays* / parasitology

Grants and funding

The present research was supported by the Federal Ministry for Economic Cooperation and Development (BMZ/GIZ) Germany (Project No.: 18.7860.2; Contract No.: 81235252) through the University of Bonn, Zentrum für Entwicklungsforschung (ZEF), Bonn, Germany. It has been carried out in partial fulfillment of a Ph.D. thesis by the first author in close collaboration with the International Centre of Insect Physiology and Ecology (icipe) Nairobi, Kenya, and the International Institute of Tropical Agriculture (IITA) Cotonou, Benin. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. There was no additional external funding received for this study.